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41.
西气东输工程中卫黄河穿越隧道长1197.77m,高4.3m,宽5.6m。隧道入口高于黄河水位28m,出口高于黄河水位45m。隧道顶板高程为1130m。位于黄河水下100m。隧道场地围岩为寒武系磨盘井组灰绿色、银灰色浅变质中厚层细粒长石石英砂岩、千枚状板岩、绢云母化千枚岩。围岩为弱风化Ⅲ~Ⅳ类岩石。透水率为4~67Lu,纵波波速为500~3300m.s-1。BQ为300~400。变形模量为6.11~9.22GPa。泊松比(μ)0.14~0.24。内摩擦角(ψ)为42.1°~44.7°。地下水为基岩裂隙水。含水层为寒武系浅变质岩,受大气降水渗入补给,单井涌水量为1.0~50m3.d-1。隧道轴线穿越区岩体较完整—较破碎,未有全新活动断层。隧道位置选择和开挖深度设计是可行的。施工和长期运营是安全的。 相似文献
42.
给出了内蒙古段黄河水平中总α,总β,^90Sr,^137Cs,^40K,^3H,^210Pb,^210Po,^238U,^232Th、^226Ra放射性水平,结果基本为正常水平,找出了污染源,为内蒙古段黄河水中放射性监督监测建立了全面的背景材料。 相似文献
43.
44.
报道了579nm高功率KGd(WO4)2喇曼晶体外腔式喇曼黄光激光器的输出特性.基于808nm脉冲激光二极管侧面泵浦Nd∶YAG陶瓷、腔内BBO电光晶体同步延迟调Q和Ⅰ类临界相位匹配的LBO晶体腔外倍频方案,并通过外腔式KGW晶体Ng轴二阶斯托克斯喇曼频移,获得了579.54nm黄光激光输出.当脉冲信号重复频率为1kHz、532nm泵浦光最高平均功率为5.02W、脉冲宽度为10.1ns时,获得了最高平均功率2.58 W、脉冲宽度7.4ns、峰值功率348.6kW的579.54nm二阶斯托克斯喇曼黄光激光输出;532nm至579.54nm的光-光转化效率为51.4%、斜率效率为54.8%,光束质量因子Mx2-579.54=5.829、My2-579.54=6.336,输出功率不稳定性小于±2.35%.实验表明:外腔式喇曼结构能够高效地获得喇曼黄光,具有很高的光-光转化效率及良好的功率稳定性,并通过脉冲LD结合同步延迟电光调Q可获得高重复频率、高平均功率、窄脉冲宽度和高峰值功率的黄光激光输出. 相似文献
45.
UV/Vis光谱法研究红子色素的稳定性 总被引:1,自引:0,他引:1
本文报导了从红子提取,分离天然色素及酸碱和温度等对该色素稳定性的影响。 相似文献
46.
Yikun Bu Quan Zheng Qinghua Xue Yingxin Cheng Longsheng Qian 《Optics & Laser Technology》2006,38(8):565-568
A design of LD-pumped Nd:YVO4 laser that generates simultaneous laser action at wavelengths 1064 and 1342 nm by optimizing film design is presented. An optimized continuous-wave (cw) yellow laser at 593.5 nm in room temperature is obtained for the first time. Using type-I critical phase-matching (CPM)LBO crystal, a yellow laser at 593.5 nm is obtained by 1064 and 1342 nm intracavity sum-frequency mixing. The maximum laser output power of 85 mW is obtained when an incident pump laser of 1.8 W is used. The optical-to-optical conversion is up to 4.7%, and the power stability in 24 h is better than ±2.8%. 相似文献
47.
Summary The aggregation behaviour of zinc-free insulin has been studied by small-angle neutron scattering as a function of protein
concentration,pH, and ionic strength of the solution. The distance distribution functions for the 12 samples have been obtained by indirect
Fourier transformation. The weight-averaged molecular mass and thez-averaged radius of gyration were determined. Both quantities vary systematically with the experimental conditions. They increase
with decreasingpH and with increasing ionic strength. The radius of gyration scales as a power law of the weight-average mass with the exponent
0.44. A similar scaling is found for a set of oligomers structures based on the crystal structure of zinc-free insulin. The
mass distribution between the oligomers was determined by a model based on these oligomers. The results from this model and
the Fourier transformations have been compared to an equilibrium model recently introduced by Kadimaet al. The model takes into account the variation of the effective charge of the monomer withpH and ionic strength. The neutron scattering results agree well with the predictions of the model.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献
48.
P. B. Warren 《Il Nuovo Cimento D》1994,16(8):1231-1236
Summary The scaling of the ratio of the hydrodynamic radius to the radius of gyration of fractal aggregates is probed by numerical
simulations for several different algorithms. In common with previous work it is found that this ratio shows a significant
and long-lasting finite-size effect for particle-cluster aggregates, but a much less significant finite-size effect for hierarchical
cluster-cluster aggregates. Simple theoretical models which reproduce the behaviour are discussed.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献
49.
Discrete simulation methods are efficient tools to investigate the behaviors of complex fluids such as dry granular materials
or dilute suspensions of hard particles. By contrast, materials made of soft and/or concentrated units (emulsions, foams,
vesicles, dense suspensions) can exhibit both significant elastic particle deflections (Hertz-like response) and strong viscous
forces (squeezed liquid). We point out that the gap between two particles is then not determined solely by the positions of
their centers, but rather exhibits its own dynamics. We provide the first ingredients of a new discrete numerical method,
named Soft Dynamics, to simulate the combined dynamics of particles and contacts. As an illustration, we present the results for the approach
of two particles. We recover the scaling behaviors expected in three limits: the Stokes limit for very large gaps, the Poiseuille-lubricated limit for small gaps and even smaller surface deflections, and the Hertz limit for significant surface deflections. We find that for each gap value, an optimal force achieves the fastest approach
velocity. The principle of larger-scale simulations with this new method is provided. They will consitute a promising tool
for investigating the collective behaviors of many complex materials. 相似文献
50.
M. Bellour A. Knaebel J.P. Munch S.J. Candau 《The European physical journal. E, Soft matter》2000,3(2):111-121
Static and dynamic light scattering and conductivity experiments were carried out on salt-free aqueous micellar solutions
of cetyltrimethylammonium n-hexane sulfonate (CTAC_6SO_3) and cetyltrimethylammonium n-heptane sulfonate (CTAC_7SO_3) as a function of surfactant concentration. This study confirms the analogy between the behavior
in the semi-dilute regime of elongated micellar systems and “classical” polyelectrolyte solutions. Time-resolved scattering
experiments performed after a variation of concentration from about twice the overlap volume fraction to less than half of it revealed the existence of a structural relaxation with a characteristic time of several hours.
Received 21 December 1999 相似文献